Campbell Scientific SDM-CD16D 16-Channel Digital Control Port Expansion Module - Manual (Page 5)

SDM-CD16D 16 Channel Digital Control
Port Expansion Module
The SDM-CD16D (see Figure 1) is a synchronously addressed peripheral. It has 16
control ports.
FIGURE 1. SDM-CD16D
1. Introduction
The SDM-CD16D expands the digital output capability of Campbell Scientific
dataloggers. The outputs can be set to 0 or 5 V by the datalogger. In addition to
being able to drive normal logic level inputs, when an output is set HI a ‘boost’
circuit allows it to source a current of up to 100 mA, allowing direct control of
low voltage valves, relays etc.
The SDM-CD16D is a synchronously addressed datalogger peripheral. Three
ports on the datalogger are used to address the SDM-CD16D then clock out the
desired state of each of the 16 control ports. Up to sixteen SDM-CD16Ds may
be addressed, making it possible to control a maximum of 256 ports from three
datalogger SDM ports.
In CRBasic, instruction SDMCD16AC is used to control the SDM-CD16D. In
Edlog, Instruction 104 is typically used; older CR7 dataloggers use Instruction
29.
Older CR7 dataloggers with pre-OS7.1 software may not have
the necessary instruction. Ensure that your datalogger contains
the appropriate instruction before using. NOTE
1