LR4 Four Channel Latching Relay Module Revision: 6/12 C o p y r i g h t © 2 0 1 0 - 2 0 1 2 C a m p b e l l S c i e n t i f i c , I n c .
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LR4 Table of Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections. 1. General Description.....................................................1 2. Specifications ..............................................................1 3. Relay Details ................................................................2 4. Contact Details.............................................................2 4.1 Types ............
LR4 Table of Contents List of Figures 1. 2. 3. 4. 5. 6. 7. LR4 Latching Relay Module...................................................................... 2 Form A - State = 1 ..................................................................................... 2 Form A - State = 0 ..................................................................................... 3 Form C - State = 1...................................................................................... 3 Form C - State = 0..............
LR4 Four Channel Latching Relay Module 1. General Description The LR4 module uses latching relays that provide the following benefits: • Low power consumption Once the control module changes the state of the relay by applying power to a coil, power can then be removed as the relay mechanically latches its state. Conventional relays require the power to be continuously present to hold a relay in one of its states.
LR4 Four Channel Latching Relay Module 3. Relay Details Relay #1 and Relay #2 Contacts: 2 independent Form A (SPST) Maximum Voltage Ratings: 30 Vdc / 30 Vac Maximum Current: Not to exceed 100 VA or 5 A Relay #3 and Relay #4 Contacts: 2 independent Form C (SPDT) Maximum Voltage Ratings: 30 Vdc / 30 Vac Maximum Current: Not to exceed 60 VA or 2 A FIGURE 1. LR4 Latching Relay Module 4. Contact Details 4.1 Types There are two different contact types on the LR4.
LR4 Four Channel Latching Relay Module FIGURE 3. Form A - State = 0 FIGURE 4. Form C - State = 1 FIGURE 5. Form C - State = 0 4.2 Relay Contact Life The expected life of the relays under no load conditions is 50 million operations. Under load, the life expectancy is reduced to 100,000 operations. Inductive loads can further reduce the life expectancy of the relay contact. Proper signal conditioning (clamping diodes) should be considered for inductive loads. 5.
LR4 Four Channel Latching Relay Module 6. LED Indicators Five LEDs are on the control module. The main status LED indicates a successful power up by turning on for one second. Rapid flashing for approximately 3 seconds indicates a power-up problem. When the status LED is on, any of the contacts that are in the 1 state will also have its LED on. In normal operation, the status LED briefly flashes once every 5 seconds. Any contact in the 1 state will have its LED flash with the status LED.
LR4 Four Channel Latching Relay Module 7.2 SDI-12 Addresses The LR4 can be set to one of ten addresses (0 to 9) which allows up to ten LR4 modules to be connected to a single digital I/O channel (control port) of an SDI-12 datalogger. The LR4 is shipped from the factory with the address set to 0. The address on the LR4 can be changed by sending an SDI-12 change-address command. The change address command can be issued from most SDI-12 recorders.
LR4 Four Channel Latching Relay Module SDI-12 Command Command Function/Description aMC! aMCn! Same as aM! aC! Concurrent Measurements Status All 4 Relays - 0 or 1 State R1, R2, R3, R4 (4 values) aCn! Concurrent Measurements Same as M1 – M8 Output is the Same as M1 – M8 aCC! aCCn! Concurrent Measurement Commands with Checksum.
LR4 Four Channel Latching Relay Module 7.4 SDI-12 Programming Examples for CRBasic Datalogger The following CRBasic examples can be used with the CR800, CR850, CR1000, CR3000, and CR5000. 7.4.1 Reading Relay Status Values The SDI-12 “M” commands can be used to read the status of the LR4 relays. Alternatively to the SDI-12 “M” commands, the LR4 also supports the “R” command.
LR4 Four Channel Latching Relay Module • The CR200(X) does not support setting all four relays in one command. The individual relay commands can only be used on the CR200(X). 'CR200(X) Set Relay #4 to State 1. SDI12Recorder(RelayState_4, "0XR;4,1!", 1.0, 0) 7.5 Edlog Set Relay Example Although this example is for the CR10X datalogger, the CR510 and CR23X are programmed similarly. Edlog dataloggers use Instruction 68 after Instruction 105 to send the extended commands.
LR4 Four Channel Latching Relay Module FIGURE 6. Communication Jumpers 8. Using Modbus The LR4 can operate in a Modbus mode. The three internal jumpers in the LR4 need to be moved from the SDI-12 position to either the RS-232 or the RS-485 position for Modbus operation. By default, the LR4 is shipped with the jumpers set for SDI-12 operation. The jumpers must be moved prior to any connection with an RS-232 or an RS-485 device (see Section 8.1, Wiring for Modbus). FIGURE 6.
LR4 Four Channel Latching Relay Module TABLE 2. Modbus/RS-232 Wiring LR4 Terminals Description Datalogger Terminal GND Power Ground and Shield G POWER Positive DC Power Source (9-30VDC) 12V SDI-12 /TX/A Modbus master RS-232 Receive COM port (Rx) RX/B Modbus master RS-232 Transmit COM port (Tx) DIG I/O Not used Not used 8.1.2 RS-485 The CR800, CR850, CR1000, CR3000, CR510, CR10X, and CR23X dataloggers can use Modbus via RS-485.
LR4 Four Channel Latching Relay Module 8.2 Modbus Baud Rate The default baud rate is 19200. Other baud rates are possible. Consult the factory if other baud rates are required. 8.3 Modbus Mode The LR4 supports RTU mode only; the ASCII mode is currently not implemented. 8.4 Modbus Address The default address assigned to the LR4 is 51. Other addresses can be assigned to the LR4 by writing the new desired address to register 9999. Once this is done, the LR4 will only respond to the new address.
LR4 Four Channel Latching Relay Module 9. Firmware Update Procedure FIGURE 7. Program Mode Jumper The firmware on the LR4 can be updated by using a terminal program such as Hyperterminal. The LR4 contains an internal female DB-9 connector to facilitate an RS-232 connection. Firmware updates should only be performed at an appropriate workstation with static control procedures in place. Failure to follow the procedures may cause damage to the device. 12 • Ensure that the LR4 is completely disconnected.
LR4 Four Channel Latching Relay Module • From the Hyperterminal menu, select Transfer Send Text File. • Select the new download text file and the transfer should begin. • Initially, the LED should remain constantly on. When data transfer begins, the LED will flash rapidly with each line that is reprogrammed. • Upon completion, the LED will remain steadily on again. • If there are any errors, the LED will flash to indicate that an error occurred.
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