Reference (Module W*)68C3 Operations Manual North Atlantic Industries, Inc. 12/19/2014Rev: 2014-12-19-0947 www.naii.com Page 294 of 330REFERENCE (MODULE W*)Reference (Module W*) - See part number designation)Principle of OperationWhen a secondary reference source is required, other than the optional on-board reference module (available oncertain model boards, see part number), the W* Reference Module can be utilized to provide an AC signal source.The single channel isolated AC output is programmable for full range voltage output from 2 to 115 VAC, andfrequency from 47 Hz to 20 KHz (see detailed specification characteristics – operation must remain within thespecified voltage/frequency/power limits.Overcurrent protection is provided via a sensing circuit which provides automatic re-try for ten seconds beforeshutdown.Suggested initialization is to program reference frequency first, reference voltage, and power on module. Thethree versions are:Module Output FrequencyCode VL-L BandW1 2-115 VRMS 47 Hz - 20 KHz (within characterized limits – see specification)W2 2-28 VRMS 47 Hz - 20 KHz (within characterized limits – see specification)W3 28-115 VRMS 47 Hz - 20 KHz (within characterized limits – see specification)Note: W1 utilizes mechanical relay for range switching. May not be suitable for some embedded system applications.Reference FrequencyType: 16-bit unsigned integerRange: 47 to 10,000 HzRead/Write: R/WInitialized Value: N/AProgram Reference Frequency, where LSB is 0.01 Hz. For example: To program 400 Hz, 400 x 100= 40,000,which equals 0x9C40. In this example, 0x0000 would be programmed in the Reference Frequency High register,and 0x9C40 would be programmed in the Reference Frequency Low register. To program 10,000 Hz, 10,000 x100= 1,000,000 which equals 0xF4240. In this example, 0x000F would be programmed in the ReferenceFrequency High register, and 0x4240 would be programmed in the Reference Frequency Low register.REGISTER D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 FUNCTION327.68163.8481.9240.9620.4810.245.122.561.280.640.320.160.080.040.020.01approximate valueREF FREQUENCY LO D D D D D D D D D D D D D D D D D=DATA BIT (Hz)REGISTER D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 FUNCTION0000000000005242.882621.441310.72655.36approximate valueREF FREQUENCY HI D D D D D D D D D D D D D D D D D=DATA BIT (Hz)
