On 10 May, 2017 - Anton Lundin wrote:
> Attached is the last iteration I did of the sensors patch. It has some
> minor differences from the one you included, but most of them isn't that
> relevant.
>
>
> The only relevant information is that the adc offset value is probably
> in 0.025 mV as unit.
> Thats party based on the information in
> https://www.shearwater.com/wp-content/uploads/2016/07/O2-Offsets-Public-Notice-RevA.pdf
>
Of course I forgot to attach the patch, so here it comes.
--
Anton Lundin +46702-161604
>From 0aa217a6f4253e12db3e440dde10647ca3a8a4c1 Mon Sep 17 00:00:00 2001
From: Anton Lundin <gla...@acc.umu.se>
Date: Wed, 14 Oct 2015 19:49:25 +0200
Subject: [PATCH] shearwater: Report individual sensor values
This reads the reported mV values from the sensors, and based on the
calibration values converts it into a ppo2 value to report.
Signed-off-by: Anton Lundin <gla...@acc.umu.se>
---
src/shearwater_predator_parser.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/src/shearwater_predator_parser.c b/src/shearwater_predator_parser.c
index fba5629..254af5b 100644
--- a/src/shearwater_predator_parser.c
+++ b/src/shearwater_predator_parser.c
@@ -69,6 +69,8 @@ struct shearwater_predator_parser_t {
unsigned int helium[NGASMIXES];
unsigned int serial;
dc_divemode_t mode;
+ unsigned int sensor_cal_value[3];
+ signed char sensor_adc_offset[3];
};
static dc_status_t shearwater_predator_parser_set_data (dc_parser_t *abstract, const unsigned char *data, unsigned int size);
@@ -297,6 +299,25 @@ shearwater_predator_parser_cache (shearwater_predator_parser_t *parser)
offset += parser->samplesize;
}
+ // Cache sensor calibration for later use
+ parser->sensor_cal_value[0] = array_uint16_be(data + 87);
+ parser->sensor_cal_value[1] = array_uint16_be(data + 89);
+ parser->sensor_cal_value[2] = array_uint16_be(data + 91);
+ // The Predator expects the mV output of the cells to be within 30mV to
+ // 70mV in 100% O2 at 1 atmosphere.
+ // If we add 1024 (1000?) to the cal value, then the sensors lines up
+ // and matches the average
+ parser->sensor_cal_value[0] += 1024;
+ parser->sensor_cal_value[1] += 1024;
+ parser->sensor_cal_value[2] += 1024;
+
+ // Cache sensor adc offset for later use
+ // Unit is probably 0.025 mV
+ // Is this included in the stored value, or its it "raw"?
+ parser->sensor_adc_offset[0] = data[93];
+ parser->sensor_adc_offset[1] = data[94];
+ parser->sensor_adc_offset[2] = data[95];
+
// Cache the data for later use.
parser->headersize = headersize;
parser->footersize = footersize;
@@ -493,8 +514,19 @@ shearwater_predator_parser_samples_foreach (dc_parser_t *abstract, dc_sample_cal
if ((status & OC) == 0) {
// PPO2 -- only return PPO2 if we are in closed circuit mode
+#ifdef SENSOR_AVERAGE
sample.ppo2 = data[offset + 6] / 100.0;
if (callback) callback (DC_SAMPLE_PPO2, sample, userdata);
+#else
+ sample.ppo2 = data[offset + 12] * parser->sensor_cal_value[0] / 100000.0;
+ if (callback && (data[86] & 0x01)) callback (DC_SAMPLE_PPO2, sample, userdata);
+
+ sample.ppo2 = data[offset + 14] * parser->sensor_cal_value[1] / 100000.0;
+ if (callback && (data[86] & 0x02)) callback (DC_SAMPLE_PPO2, sample, userdata);
+
+ sample.ppo2 = data[offset + 15] * parser->sensor_cal_value[2] / 100000.0;
+ if (callback && (data[86] & 0x04)) callback (DC_SAMPLE_PPO2, sample, userdata);
+#endif
// Setpoint
if (parser->petrel) {
--
2.9.3
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