Appendix E.    Supporting Products — List 
 
 
 
 Continuous-Analog Output (CAO) Modules 
Model  Description 
SDM-AO4A 
Four-channel, continuous analog 
voltage output 
SDM-CVO4 
Four-channel, continuous voltage and 
current analog output 
 
 
E.4.3  Relay-Drivers — List 
Relay drivers enable the CR800 to control large voltages. 
 
 Relay-Drivers — Products 
Model  Description 
A21REL-12 
Four relays driven by four control 
ports 
A6REL-12 
Six relays driven by six control ports / 
manual override 
LR4  Four-channel latching relay 
SDM-CD8S  Eight-channel dc relay controller 
SDM-CD16AC  16-channel ac relay controller 
SDM-CD16S  16-channel dc relay controller 
SDM-CD16D  16-channel 0 or 5 Vdc output module 
SW12V  One-channel 12 Vdc control circuit 
 
 
E.4.4  Current-Excitation Modules — List 
Current excitation modules are usually used with the 229-L soil matric potential 
blocks. 
 
 Current-Excitation Modules 
Model  Description 
CE4 
Four-channel current excitation 
module 
CE8 
Eight-channel current excitation 
module