LC-5 Level Controller & Flow Monitor

Transcription

1 The Level Controller and Flow Monitor provides a fully integrated Duplex Controller supporting both analog and discrete (float switch) level detection. The unit allows collecting 'rate of flow' information and the verification of the run time characteristics of the external pumps using external soft starters. The early detection of a failing pump allows a significant reduction in expensive emergency repairs and reduces the possibility of catastrophic system failures, reducing maintenance and overall operating costs. By monitoring the flow rate, the soft starter auxiliary contact and the pump seal and temperature inputs the unit ensures that the pump system is operating within specified bounds and allows the early detection of deteriorating pump performance. provides Analog level detection, Duplex pump control, pump health & run time verification, flow rate monitoring,a Bubbler controller and optional discrete (float switch) inputs. System parameters and run time statistics may be entered and viewed through the integrated HMI display or through a Modbus communications channel. In addition, the unit is supported by the LC_Config Windows based utility program for configuration, monitoring and data collection. An analog level sensor (0-10 Vdc or 4-20 ma) monitors the liquid level and provides 6 internal levels (Lockout, Off, Lead Start, Lag Start, High, Sensor Fault) for level discrimination. All inputs are provided with hysteresis and time sampling to minimize false readings caused by noise or liquid 'wave' action. Discrete (float switch) inputs may be connected as a backup to or as an alternative to the analog sensor. An integrated Bubbler controller has been designed to minimize air flow requirements and provides support for low cost analog level sensing. As a member of the Ingram Products LC family of level management products the is implemented utilizing a standard set of firmware and hardware building blocks. Features Flexible Analog level input (0-10 Vdc, 4-20 ma) Optional/Backup Discrete (float switch) inputs Handles +ve or -ve displacement Fully integrated Duplex Controller with flexible sequencing algorithm including Time of Day. Extensive Pump Health and Run Time verification. Automatic switch-over if lead pump fails Monitors inflow rate, min/max flow rate, individual pump flow rates and pump operating times Integrated Bubbler minimizes air requirements Small (126 mm X 90 mm) package Integral HMI display Modular design, compatible to entire LC Family of Level Management products Low power (12-24 Vdc, 100 ma) operation Network (Modbus) support Optional PC/Windows configuration & monitoring Data Sheet 1 10/12

2 Flow Monitor The includes an Analog Level Detector, a Duplex Pump Controller with Pump Health and Run Time Verification, Flow Rate monitoring and a Bubbler controller. In the simplest applications only the analog level detector and two pump outputs are required to provide Duplex pump control and Flow Rate Monitoring. The controller automatically selects the lead pump to operate when the level exceeds the user defined 'Lead Start' level and will switch on the 'lag' pump if the level exceeds the 'Lag Start' level. The Duplex Level Detection Duplex Pump Controller controller may be configured to alternate the two pumps between 'lead' and 'lag' roles. Pump temperature and seal leak signals allow the controller to monitor pump Health and automatically demote a pump to the 'lag only' operation the pump is not ready to operate. Flow Rate Monitor Sampling Control Pump Health Monitoring Run Time Verification is provided by monitoring an error signal provided by an external pump soft starter. This signal allows the controller to ensure that the pump is operating within specifications. Optional discrete level (float switch) inputs provide a backup to the analog level signal or may be used as the primary level detection mechanism. Bubbler Controller Pump Run Verification An integrated Bubbler controller supports both tanked and tankless bubbler systems with a sampling mechanism designed to minimize air flow requirements. HMI Display Modbus Flow rate monitoring measures the change in level over time to calculate the inflow and individual pump flow rates. The product family is built using standard hardware controllers that provide an integral HMI display and a Modbus communications option. The is provided in small (126 mm X 90 mm), DIN rail mounted controller. The integrated HMI provides access to run time statistics including flow and pump specific rates, averages, min/max values, pump operating times and pump failures. A Modbus communications port allows networking multiple LC products and supports PC based configuration, monitoring, simulation and project management. The Sensor signal may be 0-10 Vdc, or for 4-20 ma sensors a 500 ohm resistance may be connected in parallel. The Sensor input is scaled (converted to inches/feet/meters etc.) and then use to drive a 6 level discriminator. The discriminator outputs are then used to activate the required state of the internal Duplex controller. Power Sensor Health P1 Run L+ M I0 I1 I2 I3 I4 I5 I6 I7 I8 I9 IA IB IC ID P1 Man Health P2 Run P2 Man Flow O Level O O Sts O O Sts O High Air Alarm Off Lead Start Lag Start Air High Reset + OK ESC Q0 Q1 -- Q2 Q3 Q4 Q5 Q6 Q7 Purge Data Sheet 2 10/12

3 The Pump Health inputs are connected to the pump temperature relay contact and the pump seal leak detector. The verification signals connect to the external starter contact, an optional external current sensor and an optional external phase error detector for each pump. The Manual input allows each pump to be manually started and the reset signal resets pump error conditions. The and outputs indicate if a system error or warning condition exists. The and signals are connected to external pump motor starter relays, the Air, Air and Purge outputs control the bubbler sub-system. Field Wiring Controller INPUT Description AI0 (I0) AI1 (I1) I2 I3 I4 AI5 (I5) I6 I7 I8 I9 IA IB IC Sensor Input (Analog) Seal measures seal resistance Temperature detects pump temperature contact closure Auxiliary contact detects motor starter failure and/or thermal overload tripping of motor starter Manual On forces on, provided level is above the 'lockout' level Seal measures seal resistance Temperature detects pump temperature contact closure Auxiliary contact detects motor starter failure and/or thermal overload tripping of motor starter Manual On forces on, provided level is above the 'lockout' level Off Level Lead Start Lag Start High Level ID Reset reset and error status Analog signals: 0 10 Vdc or 4-20 ma (500 ohm resistor in parallel) Digital signals: 0-24 Vdc (5 volt threshold), configurable as Normally Open or Normally Closed Controller INPUT Description Q0 Q1 Q2 Q3 Q4 Q5 Q6 system warning system error output active if level is? User defined high alarm activated when should be On. activated when should be On. /Flow /Select Q7 Purge Relay Outputs: Amps, 120/ Amps (resistive), 2 Amps (inductive) Special Order: NPN or PNP outputs, 24 2 Amps Power: ma. The LC product family is UL508a compliant when used with Class II power. Slave UL508a compliant relays should be used when switching voltages greater than 48 Vdc. Data Sheet 3 10/12

4 Duplex Control with Flow Rate Monitoring The LC Family Flow Rate monitoring subsystem uses the change in levels over time and the known tank dimensions to calculate pump flow rates and flow volumes. The controller uses the pump activation by the internal Duplex controller to determine flow activity. The Duplex control subsystem of the controller performs following actions: 1. The Lead pump will turn on when the level reaches the LEAD START level 2. The Lag pump will turn on when the level reaches the LAG START level 3. Both pumps will turn off when the level drops to the PUMP OFF level In the simplest applications the Analog level detector is connected to an external sensor and the two pump control outputs are connected to the motor starter for the two pumps. When the level rises above the Lead Start level one of the two pump output signals will be activated based on the current sequencing defined by the Duplex Pump controller configuration. The status outputs may be connected to panel status lights or other control functions. Analog Level Sensor While no pumps are active the measures the the time for the liquid to rise to the Lead Start level, providing the inflow rate. When a pump is activated the inflow rate is latched (and assumed to remain relatively constant) and the controller measures the time required for the pump to lower the level to the Off level, providing the pump flow rate. The pump flow volume is the difference between the level when the pump turns on and the level when it turns off plus the volume contributed by the ongoing inflow. If after activating the first (lead) pump the level continues to rise to the Lag Start level the second (lag) pump will be activated. The flow rate of the first pump is latched and the controller then measures the flow rate of the second pump, assuming that the inflow rate and first pump flow rate remains constant. Pump Health Monitoring The health of the pump is determined by the pump temperature contact and the pump seal leak contact. The temperature contact may be configured as either a normally open or normally closed contact. If active, it indicates that the pump is over-temperature and should not be operated. The seal leak contacts measure the drop in resistance if the pump seals fail, allowing liquid past the pump seals. The resistance of a good seal will be typically > 1 Mohm. A mild leak will reduce the resistance below 100 Kohm and a severe leak will reduce the resistance below 50 Kohm. The controller accepts the seal leak inputs directly and measures the seal leak contact resistance using a simple resistive divider or will accept dry contact inputs if an external seal leak relay must be used. The controller provides separate inputs for each pump's temperature and seal leak contacts and provides both a 'warning' level and 'error' (severe) level setting for the seal leak resistance. Data Sheet 4 10/12

5 Analog Level Sensor } Temp & Seal Leak contacts } Temp & Seal Leak contacts Pump Run Time Verification Run time verification ensures that when a pump output has been activated the pump operates within specifications. The Pump activation signal is connected to an external motor soft starter error contact. The soft starter monitors the pump motor for a range of faults such as current overload, locked rotor and phase in balance. If a fault occurs a fault output relay is activated to indicate to the that an error has occurred. The controller provides separate inputs for each pump's soft starter error contact. Analog Level Sensor } Temp & Seal Leak contacts Soft Start Fault Manual Start (HOA) } Temp & Seal Leak contacts Soft Start Fault Manual Start (HOA) Manual (HOA) Start The provides two separate inputs that allow manually starting a specific pump. The manual input is only active if the level is above the zero Lockout level. Discrete Level Inputs Four discrete level inputs are provided to allow fail safe operation if the primary analog level fails. These inputs are internally connected in parallel with the analog level discriminator outputs. If the analog sensor fails the discrete level inputs will force the lead (and/or lag) pump to operate. If no analog level monitoring is used the discrete inputs may be used as the primary level sensing mechanism with an external DPDT relay connected to a discrete Lockout level float switch if required. Data Sheet 5 10/12

6 Analog Level Sensor } Temp & Seal Leak contacts Soft Start Fault Manual Start (HOA) } Temp & Seal Leak contacts Soft Start Fault Manual Start (HOA) Pump OFF level LEAD ON level LAG ON level HIGH level Bubbler Controller The provides 3 outputs that support a Bubbler control sub-system. The Bubbler sub-system supports systems with one or two pumps, with or without an air reservoir tank. To minimize air usage the bubbler outputs activate the air flow only when a level sample is required. In 2 pump systems the pumps are alternated using a user defined duty cycle. A purge output signal may be used to activate a purge function if the bubbler pressure rises above a user defined setpoint. Analog Pressure Sensor } Temp & Seal Leak contacts LC-1 Soft Start Fault Manual Start (HOA) } Temp & Seal Leak contacts Soft Start Fault Bubbler Control Purge A/Select A/Flow Manual Start (HOA) Pump OFF level LEAD ON level LAG ON level HIGH level Data Sheet 6 10/12

7 Bubbler systems use the measured air pressure required to cause bubbles to flow through a depth of liquid to determine the depth of the liquid. They offer a low cost, intrinsically safe measurement technique, requiring only a low pressure air supply (typically ~ 12 psi), pressure regulator, check valve and a pressure transducer that provides a 0-10 Vdc or 4-20 ma signal proportional to the measured air pressure. Systems without an air reservoir (tankless) activate the air pumps when a level sample is required. Systems using an air reservoir tank (tanked) activate a pneumatic valve to allow air to flow from the tank when a level sample is required. The Apump 1/Flow signal enables the flow of bubbler air (tanked systems) or activates Air (tankless).the Apump 2/Select signal selects between Air and Air (tanked systems) or activates Air (tankless). The Purge output is activated when the air pressure exceeds a user defined threshold, indicating a blocked bubbler line. Reset A single input is provided that will reset all internal errors. Individual pump errors may be reset using the integrated HMI display. External Communications The may be configured, and operating statistics are accessible using the integrated HMI display. In addition, the unit may be configured and monitored across a standard Modbus/RTU network. To connect the unit to a Modbus network the APB-EXPMC Modbus adapter may be used. The APB-DUSB adapter provides a low cost, single point adapter allowing the unit to be connected to a PC/Windows computer for configuration and monitoring purposes. LC_Config The LC_Config application program operates on a Windows based PC and provides a graphic interface for configuring and monitoring the LC Family of controllers. The configuration utility includes a set of program management tools to streamline the configuration and commissioning of devices as well as providing run time monitoring of flow data and pump performance. The LC_Config program may communicate to an device using a Modbus RTU interface through the APB-EXPMC adapter or the APB-DUSB USB adapter. Data Sheet 7 10/12

8 Specifications Specification Controller Notes Power Size Environment EMC ma 126 mm X 90 mm X 58.5 mm IEC68-2 IEC801-3 Inputs (digital) 24 Vdc (Off = 0-5, On = 10-24) & 2 Temperature, Aux Contact, Manual Start OFF, LEAD, LAG, HIGH levels Reset Inputs (analog) 0-10 Vdc, 50 kohm impedance Analog Level Detector & 2 Current monitoring Outputs Outputs (special order) Level Input Flow Run Verification Bubbler Relay 24 Vdc, 10 Amp, 240 Vac, 10 Amp resistive 240 Vac, 2 Amp inductive NPN (sink) 24 Vdc, 2 Amp PNP (source) 24 Vdc, 2 Amp 0-10 Vdc or 4-20 ma +ve/-ve displacement Gallons, Imperial Gallons, Meters Seconds, minutes, hours Auxiliary Contact closure Pump Current Pump Phase Relay contact Time filtering & Hysteresis Dual stage scaling 5 levels (Lockout, Off, On, Mid, High) Inches, feet or meters Status outputs require I/O expander. Min sample rate 0.5 sec, One or Two pumps with alternator/variable duty cycle Data Sheet 8 10/12