Cloud-electronics CDR-1B Bedienungsanleitung PDF herunterladen (Seite 8)

CDR‑1 & CDR‑1F Installation Guide v2.08

Cable length and DC power considerations

The DCM-1/e’s internal PSU has sufcient capacity to power 8 CDRs (i.e., one per

zone) provided cable runs are not excessive and good quality cable and connectors

are used. If a system has more than 8 CDRs in total, one or more additional PSUs will

certainly be required. The probability of correct operation is a function of cable length,

cable and connector quality, the number of CDRs daisy-chained, and how many of them

are at a great distance from the DCM-1/e.

The maximum recommended cable length of the CDR network for reliable data

transmission is 1 km. This gure applies either to the total cable run between the

“farthest” CDR and the DCM-1/e if a single daisy-chain of CDRs has been employed

(as in (b) on page 6), or to the total run between the most remote CDRs if the

DCM-1/e is in the “middle” of the chain (as in illustration (a) on page 6). Cable runs

longer than this may work satisfactorily, but this cannot be guaranteed. Note that the

1 km gure is a maximum over which data may be reliably transmitted, not over which

a set of CDRs may be reliably powered. In all systems, it is the power distribution which

will limit maximum cable length, not the data.

If a CDR is found to operate unreliably, it should be powered independently from a

local PSU. The Cloud CPM-PSU is suitable for this purpose, and should be connected

to the EXT POWER socket at the rear of the CDR. In the case of the CDR-1, this is

a coaxial socket, mounted vertically on the PCB to the right (viewed from the rear).

See diag. on page 11. In the case of the CDR-1F, the EXT POWER socket is a 2-pin

5 mm-pitch screw terminal type connector below the RJ45 connectors; a mating male

connector is supplied with the unit. See diag. on page 13.

Note: Wiring convention of the external PSU is unimportant, as the CDR incorporates

a bridge rectier circuit which allows it to accommodate either polarity of connection.

Note that any further CDRs connected to the POWER OUT connector will be

If a third-party external PSU is to be used, it should be rated at either 12 – 24 V DC or

9 – 17 V AC. The current consumption of a CDR is 50 mA at 12 V.

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Cloud-electronics CDR-1B Bedienungsanleitung Seite 8