Campbell Scientific AM16/32B AM16/32B Relay Multiplexer - Page 21

AM16/32B Relay Multiplexer 4.2.1 COM Terminals A CABLE3CBL, CABLE4CBL, or CABLE5CBL cable is used to connect the datalogger to the COM terminals. The CABLE3CBL is recommended when the AM16/32B is used in the 4x16 mode. The CABLE4CBL is typically used for the 4x16 mode. The CABLE5CBL is recommended for the 4x16 mode when it is desirable to connect both shields. The four terminals dedicated to multiplexer-datalogger connection are located under the blue COM next to the mode switch. The terminals are labeled: ODD H, ODD L, EVEN H, and EVEN L. In "4x16" mode the AM16/32B maintains the four COM terminals electrically isolated from one another. In "2x32" mode, the AM16/32B maintains an internal connection between ODD H and EVEN H and between ODD L and EVEN L. Common " " terminals are provided next to the COM ODD and COM EVEN terminals. They bus internally to the other thirty-two " " terminals on the AM16/32B and are connected at all times (not switched). Their function is to provide a path to ground for sensor cable shields. A COM terminal should be wired to datalogger ground via the cable's shield according to the following table. COM ODD EVEN 4X16 H L HL N O MUCXASBIGLENAL SHIELD CR10X G E1-E3 SE3 SE2 SE1 CR23X CR1000 EX1-EX4 SE3 SE2 SE1 EX1-EX3 or VX1-VX3 SE3 SE2 SE1 CR3000, CR5000 VX1-VX4 SE3 SE2 SE1 21X EXCITATION 2H 1L 1H CR7 SWITCHED ANALOG OUT 2H 1L 1H CR800, CR850 EX1-EX2 or VX1-VX2 SE3 SE2 SE1 FIGURE 4-4. Typical AM16/32B to datalogger signal hookup (4x16 mode) using CABLE4CBL cable 4.2.2 Sensor Input Terminals The terminals for sensor attachment are divided into 16 groups (panel switch set to "4x16") or into 32 groups (panel switch set to "2x32"). The groups consist of four or two Simultaneously Enabled Terminals (SETs). With panel switch set to "4x16" mode, the blue channel numbers apply. The SETs are numbered starting at 1 (1H, 1L, 2H, 2L) and continuing until SET 16 (31H, 31L, 32H, 32L). In "4x16" mode, the odd numbered terminals (example: 5H, 5L) are relay switched to the COM ODD terminals while the even terminals (6H, 6L) are switched to the COM EVEN terminals. When activated by the RES line being high, as the AM16/32B receives clock pulses from the datalogger, each SET of four in turn is switched into contact with the four COM terminals. For example, when the first clock pulse is received from the datalogger, SET 1 11