Operating Manual. Electronic Pressure and Vacuum Controllers. The Fastest Flow Controller Company in the World!

Transcription

1 Operating Manual EPCD-Series EPC-Series Electronic Pressure and Vacuum Controllers The Fastest Flow Controller Company in the World!

2 Thank you for purchasing an E-Series Vacuum and Pressure Controller. Please take the time to find and read the information for your specific device. This manual covers the following Alicat Scientific instruments: EPC-Series Vacuum and Pressure Controllers EPCD-Series Vacuum and Pressure Controllers The installation (plumbing, mounting and power/signal connection instructions are applicable to all E-Series pressure devices. Please contact Alicat at or if you have any questions regarding the use or operation of this device. TABLE OF CONTENTS Page GETTING STARTED 3 MOUNTING 4 PLUMBING 4 POWER AND SIGNAL CONNECTIONS 4 INPUT SIGNALS 5 Analog Input Signal 5 RS-232 / RS-485 Digital Input Signal 5 OUTPUT SIGNALS 6 RS-232 / RS-485 Digital Output Signal 6 Standard Voltage (0-5 Vdc) Output Signal 6 EPC-SERIES SINGLE VALVE PRESSURE CONTROLLER OPERATION 6 EPCD-SERIES DUAL VALVE CONTROLLER OPERATION 6 RS-232 OR RS-485 OUTPUT AND INPUT 7 Flow Vision Software 7 Additional Compatible Programs 7 Sending a Command 7 Polling Mode 7 Streaming Mode 8 Data Format 8 Sending a Setpoint via RS-232 / RS Sending a Setpoint to a Controller with Negative and Positive Range via RS-232 / RS PID Tuning 9 MAINTENANCE AND RECALIBRATION 10 Technical Data for EPC and EPCD Pressure Controllers 11 Notice: Alicat Scientific, Inc. reserves the right to make any changes and improvements to the products described in this manual at any time and without notice. This manual is copyrighted. This document may not, in whole or in part, be copied, reproduced, translated, or converted to any electronic medium or machine readable form, for commercial purposes, without prior written consent from the copyright holder. Note: Although we provide assistance on Alicat Scientific products both personally and through our literature, it is the complete responsibility of the user to determine the suitability of any product to their application. Conformity / Supplemental Information: The product complies with the requirements of the Low Voltage Directive 2006/95/EC and the EMC Directive 2004/108/EC and carries the CE Marking accordingly. Contact the manufacturer for more information. 06/30/2017 Rev.2 DOC-EPCMAN 2

3 GETTING STARTED Outlet Connection Port Inlet Connection Port EPC-Series Pressure Controller* Description Date Inlet Connection Port Vent Port Outlet Connection Port EPCD-Series Pressure Controller* * Port positions may vary according to build. 3

4 MOUNTING EPC and EPCD-Series Controllers have mounting holes for convenient mounting to flat panels. These controllers are position insensitive and can be mounted in any orientation. The sizes and dimensions for the mounting holes are shown on page 11. Minimize physical handling of the exposed circuit board of the EPC or EPCD while installing. Hold the circuit board on its edges while installing, in order to minimize contact with the exposed circuit board of the EPC or EPCD. PLUMBING Your instrument is shipped with plastic plugs fitted in the port openings. To lessen the chance of contaminating the flow stream do not remove these plugs until you are ready to install the device. Controllers with M5 (10-32) ports have O-ring face seals and require no sealant or tape. Do not use tape with welded or O-ring fittings. For non M5 (10-32) ports use thread sealing Teflon tape to prevent leakage around the port threads. Do not wrap the first two threads. This will minimize the possibility of getting tape into the flow stream and flow body. Do not use pipe dopes or sealants on the process connections as these compounds can cause permanent damage to the controller should they get into the flow stream. When changing fittings, carefully clean any tape or debris from the port connections. POWER AND SIGNAL CONNECTIONS Power can be supplied to your controller through the 6 pin Micro-Fit connector. Standard 6 Pin Micro-Fit Pin-Out Pin Function Cable Color 1 DC Power input Red 2 Analog Out Brown 3 Ground Black 4 Serial RS-232TX / RS-485(+) Blue 5 Serial RS-232RX / RS-485(-) White 6 Analog Setpoint Input Green CAUTION! Do not connect power to pins 2 through 6 as permanent damage can occur! CAUTION! Exceeding the maximum specified line pressure may cause permanent damage to the solid-state pressure transducer. 4

5 INPUT SIGNALS Analog Input Signal Standard 0-5 Vdc : Apply analog input to Pin 6 as shown on page Vdc is the standard analog input signal. Apply the 0-5 Vdc input signal to pin 6, with common ground on pin 3. Optional 0-10 Vdc: If specified at time of order, a 0-10 Vdc input signal can be applied to pin 6, with common ground on pin 3. Optional 4-20 ma: If specified at time of order, a 4-20 ma input signal can be applied to pin 6, with common ground on pin 3. NOTE: This is a current sinking device. The receiving circuit is essentially a 250ohm resistor to ground. CAUTION! Do not connect this device to loop powered systems, as this will destroy portions of the circuitry and void the warranty. If you must interface with existing loop powered systems, always use a signal isolator and a separate power supply. Wiring your EPC Cable into a DB9 RS-232 or RS-485 adaptor To use the RS-232 or RS-485 input signal, connect the RS-232 / RS 485 Output Signal (Pin 5), the RS-232 / RS 485 Input Signal (Pin 3), and Ground (Pin 8) to your computer serial port as shown below. (See page 7 for details on accessing RS-232 / RS 485 input.) Serial Cable End PC Serial Port 9 Pin Serial Connection 6 Pin Micro-Fit Connection Pin Function Function Pin 6 Ground Ground 1 5 Transmit Receive 2 4 Receive Transmit 3 DB9 to Micro-Fit Connection for RS-232 / RS-485 Signals Please Note: DB9 adaptor drawings shown represent the face of the cable, wiring ports at the back of the adaptor will be mirrored. 5

6 OUTPUT SIGNALS RS-232 / RS-485 Digital Output Signal To use the RS-232 or RS-485 output signal, it is necessary to connect the RS- 232/ RS-485 Output Signal, the Input Signal, and Ground to your computer serial port as shown on page 5. (See page 7 for details on accessing RS-232 / RS-485 output.) Standard Voltage (0-5 Vdc) Output Signal Controllers equipped with a 0-5 Vdc will have this output signal available. This voltage is usually in the range of Vdc for zero flow and 5.0 Vdc for full-scale flow. The output voltage is linear over the entire range. Ground for this signal is common on Pin 3. Other output options include 0-10 Vdc, 1-5 Vdc and 4-20 ma. EPC-SERIES SINGLE VALVE PRESSURE CONTROLLER OPERATION Alicat Scientific EPC-Series Pressure Controllers incorporate a digital pressure gauge with a single control valve and circuitry. The integrated PID loop measures the pressure, compares it with the setpoint, and adjusts the valve accordingly at 1000 times per second. The response time of the system will depend on the operating conditions and the PID tuning of the device. Plumbing EPC-Series Pressure Controllers are normally intended to control the process pressure downstream of the controller. In order for this to occur, a supply pressure greater than the full scale pressure control range of the device, not to exceed 150 psig, should be connected to the IN port. EPCD-SERIES DUAL VALVE PRESSURE CONTROLLER OPERATION Alicat Scientific EPCD-Series Closed Volume Pressure Controllers incorporate a digital pressure gauge with dual control valves and circuitry. The integrated PID loop measures the pressure, compares it with the setpoint, and adjusts either the Inlet or Exhaust valve accordingly at 1000 times per second. The response time of the system will depend on the size of the volume being controlled, the operating conditions, and the PID tuning of the device. The controllers are intended for use with clean, non-corrosive gases only. They are designed with a feed port, a process port, and an exhaust port. This allows the controllers to raise and lower the pressure of a closed system within the operating range of the controller without wasting gas under constant pressure conditions. Plumbing EPCD-Series Dual Valve Pressure Controllers are commonly ordered with custom port locations. Connect your EPCD into your process via the OUT port of the unit. This is the Process port. Connect a supply pressure greater than the full scale pressure control range of the device, not to exceed 150 psig, to the IN port. The VENT port can vent to atmosphere if the application is suitable, or to a collection network if necessary. The pressure at the vent port should be at atmospheric pressure or below to allow the controller to be used over its full scale range. 6

7 RS-232 / RS-485 OUTPUT AND INPUT EPC and EPCD pressure instruments come standard with integrated multi-drop RS-232 or RS-485 as ordered. Flow Vision Software Flow Vision is an affordable software program that interfaces with RS-232 or RS-485 and is compatible with most of the aforementioned flow and pressure instruments. The graphical user interface (GUI) provides automatic configuration, session saving for easy configuration and experiment setup reloads, data capturing and logging (including a graphing tool), simple script building for automating meter and control command sequences, software alarms and support for multiple devices. Flow Vision SC is for general use with up to 26 different devices, while Flow Vision MX is specifically designed for gas mixing applications. Additional Compatible Programs: Many serial communication type software packages including PuTTy and LabVIEW are also compatible with these instruments. To set up serial communication it is important to note which COM port the device is connected to and the baud rate on the device (default 19200). It may also be useful to make sure the program will move to the next line when pressing Enter or Return. The number of data bits should be set to 8, and the number of stop bits should be set to 1. Parity and flow control should be disabled. Not all programs have these options and care should be taken to determine the proper communication setup with the desired program. Sending a Command In this section, a command will be denoted with a different font. For example, command<cr>. <CR> will be used to symbolize a carriage return. How a carriage return is entered is dependent on the serial communication program being used. With Serial Terminal, this can commonly be accomplished by pressing Enter or Return. Parenthesis denote a value that must be filled in by the user. For example,(unit ID)<CR> should be changed to A<CR> when using a device with Unit ID A. It may also be useful to note that commands are case insensitive. For example, A<CR> is equivalent to a<cr>. Polling Mode All Alicat devices are sent in Polling Mode with Unit ID A unless otherwise requested. Polling a device will return a data frame of the current measurements in the device in units shown on the display. See Data Format, later in this section, for more information. Each unit may be polled individually using the command (unit ID)<CR>. A device s Unit ID may be changed using the command (current unit ID)@=(desired unit ID)<CR>. The Unit ID can also be changed via the front panel using the RS-232 / RS-485 communication select menu. Care should be taken not to assign the same unit ID to more than one device on a single COM port. Up to 26 units may be connected simultaneously as Unit IDs between A and Z are allowed. 7

8 Streaming Mode (RS-485 units do not have streaming mode) In Streaming Mode, a device will automatically output the data stream at a predetermined rate. The default rate is set to 50 ms. Only one unit on a given COM port may be in streaming mode at a time. To change a unit from Polling Mode to Streaming Mode, type (unit ID)@=@<CR>. This is equivalent to changing the unit ID If data does not appear, check all the connections and COM port settings. When sending a command to a unit in streaming mode, the flow of information will not stop while the user is typing; and the typed text may not be readable depending on the terminal settings. If the unit does not receive a valid command, it will ignore it. If in doubt, simply perform another carriage return and start again. To change a unit from Streaming Mode to Polling Mode, ID)<CR>. If entered correctly, the data stream will stop and the device will now be in polling mode. Data Format The data frame on the screen represents the current measurements in the device in the units shown on the display. By default, pressure controllers are configured to output three columns of data All data is displayed in the device units selected on the unit. Devices come standard with units of PSIA or PSIG, depending on the type of the device. The first column is the unit ID. This column will be excluded if the device is in streaming mode. The next column is pressure, and the third column will display setpoint. For example, suppose a controller with unit ID A was ordered with units of inhgg and currently has a setpoint value set to inhgg. The data frame may read: A Unit ID Pressure Setpoint EPC/EPCD-Series Pressure Controller Data Format Additional columns, including status codes, may be present to the right of the last column. Sending a Setpoint via RS-232 / RS-485 EPC s can be ordered in analog input mode or in RS-232/RS-485 input mode. If you ve ordered the EPC in RS-232/R-S485 input mode the following section will provide instructions on sending a setpoint via RS-232/RS-485. If you ve ordered the EPC in analog input mode and wish to change over to RS-232/RS-485 input mode, you must read and adjust register 20 in the 16 bit programming of your EPC. Please contact the factory for instructions on changing from Analog to RS-232/RS-485 input mode via RS-232/RS-485 adjustment. To send a setpoint via RS-232 / RS-485: Method 1: Setpoint may be set as a floating point number in serial communication using the setpoint command (unit ID)S(floating point number)<cr>. For example, AS4.54<CR> changes the setpoint for unit A to 4.54 in the current device units. Method 2: The setpoint can also be set in reference to a portion of the full scale. Type (unit ID)(integer)<CR>. Values between 0 and are acceptable, which correspond linearly to 0 and 100% full scale flow respectively. Once a setpoint is accepted, the data frame will be returned with the setpoint column changed accordingly. 8

9 The formula for performing linear interpolation is as follows: Value = (desired setpoint) X / (full Scale) For example, when changing the setpoint on a 100 PSIA full scale controller to 35 PSIA, the following value should be entered: = (35 PSIA) X / (100 PSIA) Sending a Setpoint to a Controller with Negative and Positive Range via RS-232 / RS-485 For a controller with a negative and positive range, the setpoint command may be sent in either of the above two methods with the following changes: Using Method 1, a negative setpoint may be set using a negative sign in the command. For example, AS-4.54<CR> changes the setpoint for units A to in the current device units. Using Method 2, values between 0 and are acceptable which correspond linearly to the minimum and maximum pressure, respectively. The formula to perform linear interpolation for a negative and positive ranged controller is as follows: Value = (desired setpoint + minimum pressure) X / (maximum pressure - minimum pressure) For example, when changing the setpoint on a -10 PSIG to 10 PSIG ranged controller to -3 PSIG, the following value should be entered = (-3 PSIG PSIG) X / 10 PSIG- (-10 PSIG) PID Tuning your EPC and EPCD over RS-232/RS-485: The EPC and EPCD series of pressure controllers have an integrated PID loop that measures the pressure, compares it with the setpoint, and adjusts the valve accordingly at 1000 times per second. This PID tuning governs the control speed, control stability, overshoot, and general performance of the EPC or EPCD. If you encounter issues with valve stability, oscillation or speed, fine tuning these parameters may resolve the problem. Alicat controllers allow you to adjust the Proportional, Integral and Differential terms of the PID control loop. Knowing how to change PID tuning, and knowing how to do it correctly and attain the results you desire are two very different things. The following section covers the theory/operational characteristics of the PID parameters: The PD algorithm is the PID algorithm used on most Alicat controllers. It is divided into two segments: The first compares the process value to the setpoint to generate a proportional error. The proportional error is multiplied by the P gain, with the result added to the output valve drive. The second operates on the present process value minus the process value during the immediately previous evaluation cycle. This velocity term in multiplied by the D gain, with the result subtracted from the output valve drive. The above additions to and subtractions from the output drive register are carried over from process cycle to process cycle, thus performing the integration function automatically. Increasing the P gain will promote the tendency of the system to overshoot, ring, or oscillate. Increasing the D gain will reduce the tendency of the system to overshoot. 9

10 The PD2I algorithm is a PID algorithm used primarily for high performance pressure and flow control applications. It exhibits two basic differences from the PD algorithm that most controllers utilize. 1. Instead of applying a damping function based upon the rate of change of the process value, it applies a damping function based upon the square of the rate of change of the process value. 2. The damping function is applied directly to the proportional error term before that term is used in the proportional and integral functions of the algorithm. This provides a certain amount of look ahead capability in the control loop. Because of these differences, you will note the following: 1. Increasing P gain can be used to damp out overshoot and slow oscillations in pressure controllers. You will know that P gain is too high, when the controller breaks into fast oscillations on step changes in setpoint. On flow controllers, too low a P gain results in slower response times. Too high a P gain results in overshoot and/or slow oscillation. A good starting value for P gain is If the unit was originally shipped with the PD2I algorithm selected, the D gain value should be left at or near the factory setting because it relates primarily to the system phase lags. If you are changing from the default algorithm to the PD2I algorithm, you should start with a D gain value of The I gain is used to control the rate at which the process converges to the setpoint, after the initial step change. Too low a value for I gain shows up as a process value that jumps to near the setpoint and then takes awhile to converge the rest of the way. Too high a value for I gain results in oscillation. A good starting value for the I gain is 200. MAINTENANCE AND RECALIBRATION General: EPC and EPCD-Series controllers require minimal maintenance. The single most important thing that affects the life and accuracy of these devices is the quality of the gas being measured. The instruments are designed to measure clean, dry, non-corrosive gases. Recalibration: The EPC device is an OEM product calibrated to NIST traceable standards at the time of manufacture. As an OEM device there is not a factory recommended periodic recalibration cycle. Recalibration can be requested at the user s discretion/requirement. Before calling to schedule a recalibration, please note the serial number on the back of the device. Cleaning: EPC and EPCD-Series controllers require no periodic cleaning. If necessary, the outside of the controller can be cleaned with a soft dry cloth. Avoid excess moisture or solvents. For repair, recalibration or recycling of this product, contact: Alicat Scientific, Inc N Business Park Drive Tucson, Arizona USA Ph Fax service@alicat.com Web site: 10

11 Technical Data for EPC and EPCD Pressure Controllers Alicat EPC-Series controllers allow the precise control of absolute or gauge pressure. These units can be configured for vacuum pressure or back pressure control. EPCD-Series are dual valve controllers that accurately and efficiently control pressure within a closed system with a minimum loss of expensive gases through the exhaust process. Standard Specifications (Contact Alicat for available options.) Performance EPC & EPCD Controllers Full scale pressure 2 H2O Standard Accuracy ± 0.125% Repeatability Zero Shift and Span Shift Operating Range / Turndown Ratio Excess Pressure Burst Pressure Typical Response Time 1 Warm-up Time ± 0.05% Full Scale 0.01% Full Scale / ºCelsius 0.5% to 100% Full Scale / 200:1 Turndown 102.4% FS Controllable 3 X Full Scale 100 ms (Adjustable) < 1 Second 1. Volumes, feed pressures, exhaust pressures and line sizing will determine the limits of response times. Operating Conditions Gas Compatibility Operating Temperature Mounting Attitude Sensitivity Valve Type Wetted Materials EPC & EPCD Controllers Compatible with all non-corrosive gases -10 to +60 ºCelsius None Normally Closed 400 Stainless Steel, 302 & 303 Stainless Steel, Viton. Silicone RTV, Silicon, Glass, Nickel, Brass, Aluminum, BUNA-N. If your application demands a different material, please contact Alicat. Communication / Power EPC & EPCD Controllers Digital Input / Output Signal 1 Options RS-232 Serial / RS-485 Serial / Modbus Analog Input / Output Signal 2 Options 0-5 Vdc / 1-5 Vdc / 0-10 Vdc / 4-20 ma Electrical Connection Options 6 Pin Micro-Fit Supply Voltage Vdc (15-30 Vdc for 0-10Vdc and 4-20 ma outputs) Supply Current Amp 1. The Digital Output Signal communicates Pressure. 2. The Analog Output Signal communicates Pressure Mechanical Specifications Pressure Product Mechanical Dimensions Process Connections EPC Controllers Vary with build Female / 1/8 NPT Female EPCD Controllers Vary with build Female / 1/8 NPT Female Standard Available Ranges EPC & EPCD Controllers -15 psig to 0 psig 1 psig 2 inh2og 5 psig 4 inh2og 15 psig 10 inh2og 15 psia 30 psig 20 inh2og 30 psia 100 psig 100 psia 300 psig 300 psia Custom ranges available. 11

12 EPC-Series: Dimensions and port locations may vary according to build N Business Park Dr. Tucson, AZ Ph Fax EPCD-Series: Dimensions and port locations may vary according to build N Business Park Dr. Tucson, AZ Ph Fax 12